This measurement comes up a lot in my E&M class, in regards to inductance and inductors.
Is there really no conventional term for this?
If not, is there some historical reason for this omission?
Nope, not as far as I know. It's just "rate of change of current" or something like that.
I suppose it's possible someone has given it a name in some paper or textbook, but if so, it's not widely used.